No System.Runtime.Caching available?

You just need to add a reference to the System.Runtime.Caching assembly.

1. In solution explorer, right-click on “References”
2. Select “Add reference”
3. From left side menu select “Assemblies”
4. Look for (or filter) and add System.Runtime.Caching.dll.

It’s not part of the default set of references in a class library, but you should be able to add it with no problems.